Abstract
This chapter reviews the microwave dielectric properties of materials having a high εr. BaO-Ln2O3-TiO2 system has attracted much scientific and commercial interest due to their high permittivity, high quality factor, and low temperature coefficient of resonant frequency. In the BaO-Ln2O3-TiO2 system dielectric constants are found to be affected by three factors: volume of the octahedron, tilting of the octahedron, and polarizabilities of Ln and Ba ions. The relative permittivity is found to increase with lattice parameters or cell volumes. Eu, Sm, and Nd based compounds have high quality factors (Qf) up to about 14, 000 GHz and the La-based ceramics show the highest relative permittivity. The lead-based relaxor materials such as (Pb,Ca)ZrO3, (Pb,Ca)HfO3, and (Pb,Ca) (Fe,Nb)O3 having a high relative permittivity and small temperature coefficient of permittivities are extensively investigated for multilayer capacitor applications. Recently Ag(Nb1-x Tax)O3 was reported as a high permittivity and low-loss dielectrics for microwave applications.
Original language | English |
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Title of host publication | Microwave Materials and Applications |
Pages | 192-202 |
Number of pages | 11 |
ISBN (Electronic) | 9781119208549 |
DOIs | |
State | Published - 10 Apr 2017 |
Keywords
- Ag(Nb1-x Tax)O3
- BaO-Ln2O3-TiO2 system
- High permittivity materials
- Microwave applications
- Microwave dielectric properties
- Sr1-3x/2CexTiO3 ceramics
- Temperature coefficient